Arthur Harry Hoffman- son of Catherine Barnes who is daughter of John Haddock Barnes

This a a photo of my grandfather- Arthur Harry Hoffman. His mother - Catherine Ellen Barnes (b 1845-1846) was the eldest daughter of John Haddock Barnes and Margaret Cotter of Lockport, NY). She's my great grandmother. Am searching for info on her and her 1st husband - Edward or John Hoffman. He disappears after 1870. They had a daughter Edith T (b abt 1868, Dakota Territory and a son, Arthur Harry (b somewhere in PA, abt 1870). Catherine and children live in Iowa, near her siblings and mother Margaret in 1870. Catherine leaves her son with Barnes family who move on and settle in Omaha, Nebraska. Catherine marries Charles Hill in Montana (1877) and they all settle in Minneapolis, MN in 1883. She dies in Minneapolis in 1905. Any info/photos welcome, especially if it's info on her 1st husband! Attached is tinted photo of my grandfather, Arthur Harry Hoffman in hopes that someone sees a resemblance.

Started out simply enough, but more answers led to more questions. Family surnames: Hoffman (from PA), Barnes (from CT to NY to the Midwest and beyond) and Myers from Glanworth, Ireland to Minneapolis, MN